An injection valve for injecting an air-fuel mixture, in which an orifice element consisting of a silicon injection plate is used, is described in German Published Patent Application No. 41 12 150. The silicon injection plate is manufactured by bonding an upper silicon plate with a lower silicon plate. The upper silicon plate has injection holes. The lower silicon plate has at least one through hole. In addition, recesses are introduced into the silicon plates to form conduits connecting the through hole to an outer edge of the silicon injection plate. Air, for instance, is blown in or suctioned in through these conduits thereby guaranteeing an improved atomization of the liquid flowing through the injection holes. The silicon plates are fabricated by anisotropic etching.
U.S. Pat. No. 4,907,748 likewise describes an injection valve that employs an orifice element (silicon nozzle plate) consisting of two silicon plates coupled to one another. The spray-discharge openings of the upper plate and the passthrough opening of the lower plate are offset from one another. The plates are used for preparing (or metering) fuel and not for dosing (i.e., quantitatively regulating) a gas surrounding the fuel.
U.S. Pat. No. 4,828,184 describes a nozzle which comprises two silicon plates. The first silicon plate has at least one opening formed therethrough, and the second silicon plate has precisely one opening formed therethrough. The openings of the first and second silicon plates are offset from one another. Regions of reduced thickness are formed between the plates thereby forming a shear gap between the openings of the first plate and the opening of the second plate. In each case, the shear gap is parallel to the end faces of the plates.
All of the above-mentioned injection valves produce a more or less compact single jet of fuel or of another medium being discharged. Unfortunately, the above-mentioned injection valves are not well suited for producing a dual-jet characteristic for the fuel, which is desired, for instance, during the spray-discharging on to two intake valves of an internal combustion engine. Thus, there exists a need for an injection valve which simply and cost-effectively produces a dual-jet characteristic for a medium to be sprayed in a very narrow space.